The present invention relates to a novel poly(disulfonyl diazomethane) compound suitable as a radiation-sensitive acid-generating agent in a positive-working chemical-amplification photoresist composition and a photoresist composition containing the same. More particularly, the invention relates to a poly(disulfonyl diazomethane) compound capable of generating bulky sulfonic acid molecules by the irradiation with actinic rays and a positive-working chemical-amplification photoresist composition containing the same capable of giving a patterned resist layer of high pattern resolution having an excellently orthogonal cross sectional profile with high photosensitivity.
It is a trend in recent years that, in the photolithographic patterning technology for the manufacture of semiconductor devices, liquid crystal display panels and the like, so-called chemical-amplification photoresist compositions are more and more widely employed as the photoresist. A chemical-amplification photoresist composition utilizes the catalytic activity of an acid generated from a radiation-sensitive acid-generating agent as an essential ingredient of the photoresist composition in the areas pattern-wise exposed to actinic rays. Accordingly, chemical-amplification photoresist compositions are advantageous in respect of the high photosensitivity and excellent pattern resolution even with a relatively low content of the radiation-sensitive acid-generating agent in the photoresist composition.
Chemical-amplification photoresist compositions, which are classified into the positive-working type and negative-working type, each comprise, in general, a radiation-sensitive acid-generating agent and a film-forming resinous ingredient capable of changing the solubility behavior in an aqueous alkaline solution by interacting with the acid generated from the acid-generating agent in the areas irradiated pattern-wise with actinic rays.
The film-forming resinous ingredient most widely employed in the above mentioned positive-working photoresist composition of the chemical-amplification type is a polyhydroxystyrene resin of which a part of the hydroxyl groups are substituted by acid-dissociable solubility-reducing groups such as tert-butoxycarbonyl group, tetrahydropyranyl group and the like. In the negative-working chemical-amplification photoresist compositions, on the other hand, the film-forming resinous ingredient is usually a combination of a resinous ingredient such as the above mentioned polyhydroxystyrene substituted for a part of the hydroxyl groups by the solubility-reducing groups, polyhydroxystyrene or novolak resin with an acid-crosslinkable compound such as melamine resins, urea resins and the like.
Along with the trend in recent years for an increasing fineness in the photolithographic patterning in the manufacture of semiconductor devices, intensive investigations are now under way for the development of the photolithographic technology capable of accomplishing a fineness of about 0.25 .mu.m in pattern resolution by employing a chemical-amplification positive-working photoresist composition. As to the light source for pattern-wise exposure of the photoresist layer, investigations are also undertaken for the use of KrF excimer laser beams of 248 nm wavelength by which a still finer pattern resolution of smaller than 0.25 .mu.m could be accomplished to comply with the requirement in the semiconductor devices of next generation.
While various types of radiation-sensitive acid-generating compounds have been proposed in the formulation of chemical-amplification positive-working photoresist compositions, diazomethane compounds having a single -SO.sub.2 -C(N.sub.2)-SO.sub.2 -linkage in the molecule disclosed in U.S. Pat. No. 3,332,936 and British Patent 1,231,789 form a class of promising acid-generating agents in a chemical-amplification photoresist composition as is disclosed in Japanese Patent Kokai 2-118655, 2-84648, 2-187764, 3-103854, 4-210960 and 4-217249.
The above mentioned diazomethane compounds, however, are not quite satisfactory for use in the modern photolithographic patterning works requiring extreme fineness of 0.25 .mu.m or finer in the pattern resolution because such fine resolution of pattern cannot be accomplished by using the diazomethane compound if not to mention the problem of a poor cross sectional profile of the patterned resist layer.